Radio advertising is one of the oldest forms of advertising. In the early 20th century, as radio began to take center stage in a lot of American homes, businesses realized that they could use this medium to reach a huge audience for their products, and not merely rely on print media such as newspapers and pamphlets.
Advertisers can buy airtime from a radio station to air their ads, and prices depend upon the duration, time of the day, and the programs during which the ads are aired. According to market research firm Arbitron, over 240 million people in the United States tune in to the radio at least once a week. Radio has been given a much-needed boost as a medium of communication, and therefore of advertising, with the advent of online radio broadcasts.